The subject of the present invention is a cross-country ski binding in particular a cross-country ski binding that facilitates more efficient kinematics and thus improved force transmission.
A binding such as this is known from document U.S. Pat. No. 6,017,050, the content of which is incorporated by reference. It encourages forward motion when performing the gliding step, the energy stored up in the spring exerting thrust on the ski. It also makes sure that the ski returns to against the boot when performing the skating step, during the so-called return phase when the ski is lifted from the ground and runs at an angle with respect to the general direction of travel, before being brought forward perpendicularly to the actual direction of travel.
In this binding, the link rod is articulated to the body of the binding behind its point of attachment, that is to say toward the heel of the ski, and its spring is itself attached to the body of the binding at a point located behind the articulation. The latch actuating lever, articulated in the front part of the body of the binding, actuates the latch positively both for closing and opening it and means are provided for keeping the lever in the closed position, folded down onto the ski. This construction requires a relatively long and bulky binding body. Furthermore, the maximum angle that the boot can adopt with respect to the ski as it pivots about the front bar is relatively small, of the order of 20xc2x0. This amount of movement is not sufficient for the pushing phase.
Bindings for ski touring or cross-country skiing are also known and comprise a plate equipped with means for binding the boot to the plate, this plate being articulated at the front to a base or auxiliary plate and connected to the base or respectively to the plate fixed to the ski, by a spring.
A cross-country ski boot with two binding bars is also known from patent EP 0 620 711.
A cross-country ski binding for a boot is provided, the sole of which is equipped with two parallel transverse bars located in the front part of the boot. The binding comprises a binding body on which is mounted a retainer for retaining the front bar. The retainer comprises a moving latch and a latch operating lever and a link rod articulated to the body. The link rod ends in a hook which catches on the rear bar of the boot, this rod being urged by at least one tension spring and having an engagement ramp for the rear bar. A stop keeps the link rod in a position that allows its hook to engage on the rear bar when the boot is stepping into the binding. The spring allows the boot to lift by rotation about its front bar while at the same time storing up energy which is restored in the form of elastic return returning the ski against the boot.
The binding according to the invention is one wherein the link rod is articulated at a point located forward of its hook and the spring is attached by one of its ends to the link rod and by its other end to a point located between the hook of the link rod and the front bar locking point.
A construction such as this is particularly compact. It can be housed in an interruption in the profile of a profiled ski. The position of the link rod articulation allows the boot an angular travel relative to the ski that is appreciably greater than is allowed in the binding according to the prior art, and can achieve this with a shorter link rod. Furthermore, mounting the operating lever on the body of the binding is also simplified. The front part of the body of the binding can be shortened and the operating lever can be profiled so that it can be folded down onto the profile of a profiled ski, on each side thereof.
According to one embodiment, the spring is attached to the latch. The closure of the binding is made easier because all that is required is for the lever to be pushed down partially, the spring taking on the task of completing the travel of the lever and of folding it down onto the ski, in which position the lever is held by the spring. The spring thus has three functions: pulling on the link rod, holding the latch in the closed position and holding the operating lever in the folded-down position.
According to another embodiment, the spring is attached to the body of the binding and the latch is not urged by the spring or by any other spring.
The object of the invention is to overcome the aforementioned drawbacks of the binding of the prior art.